Wednesday, November 05, 2003

Who uses adjuncts? School and student selection 

I am waiting for Invisible Adjunct to discuss this article about the effects of using adjuncts on student learning. Ideally here at SCSU, we use adjuncts to cover topics for which we do not have full-time faculty sufficiently trained. I went to a small liberal arts school, for example, that allowed a local lawyer to come in to teach business law. This seems meet and right. But as the article notes and as IA has discussed for months, there has been a much greater reliance on adjuncts over the last fifteen years. I bring up this piece because it has a very interesting result: The students who take courses from adjuncts are not a random sample of the student body. Instead, students with higher ACT scores tend to take more classes from full-time faculty. So while there are results suggesting that dropout rates are higher when more adjuncts are used, there is the simultaneous problem (or "student selection bias") that schools that use more adjuncts also draw more students that may not succeed at school (if ACT scores are a predictor of student success, which I realize will raise a red flag with some.) The size of that effect might not be too large, though, as the result seems to depend greatly on what field you go into. Looking at two students in the same subject area, the one with a 10% higher ACT score is only 0.8% less likely to take a course with an adjunct. There also doesn't seem to be any effect of the use of adjuncts on taking subsequent courses in a particular field, pass rates for subsequent classes, or on dropout rates. What they do, however, is increase the enrollment in classes. That is, use of adjuncts has probably increased the availability of courses for students; the magnitude of the effect, however, doesn't appear to be very large.